Which of the following options is NOT a common construction quality defect in ceiling works?

The common problems of exterior wall brick engineering are mainly hollowing, falling off and cracking. In order to control the emergence of these problems, it is necessary to standardize the construction, as follows:

1. Prevent falling off, hollowing and cracks. During construction, the base must be cleaned, the surface repaired and smoothed, and the wall surface is soaked with water. Before the use of exterior wall tiles, they must be soaked in water for no less than 2 hours, and then taken out to dry before they can be pasted.

The external wall brick adhesive mortar is too thick or too thin to produce hollowing, and the thickness is generally controlled to 7 10mm. If necessary, the 108 glue of cement quality 3 is mixed to improve the workability and water retention of the adhesive mortar; When bonding the exterior wall bricks, gently tap the brick surface with the ash spoon wooden handle to make it dense and firm with the bottom layer. During winter construction, anti-freezing and warmth measures should be taken to ensure that the mortar is not frozen.

2. Prevent uneven seams and uneven seam widths. Before construction, carefully select the exterior wall tiles and remove the defective exterior wall tiles. Apply the same size exterior wall tiles on the same wall to achieve uniform joints.

Do a good job of rules before pasting, paste ash cake with exterior wall bricks, draw out the standard, and wipe straight on both sides at the sunny corner. Each row of exterior wall tiles should be used in time to straighten horizontally and vertically, and the deviation should be gently knocked flat with an ash spoon wooden handle, and the horizontal and vertical joints should be corrected in time.

3. After hooking or wiping the joints, the mortar and paint on the surface of the brick should be wiped with a rag or cotton yarn in time.

4. When inlaying exterior wall facing bricks in summer, a ventilation pergola should be erected to prevent exposure to the sun and other reliable and effective measures should be taken.

5. During the construction in winter, the use temperature of the mortar shall not be lower than 5, and anti-freezing and warmth measures should be taken before the mortar is hardened. Walls built with the freezing method should be defrosted before plastering.

Options, I don't see pictures or text or anything like that.

A: What about the following options? Please complete it. ‍

13. Which of the following options does not belong to the common construction quality defects of ceiling projects. (A) The spacing between the booms is too small.

B. Asymmetry of the block.

C. Cracks and unevenness in the ceiling.

D. The boom is not vertical and not rust-proof.